1. Field of the Invention
This invention relates to a semiconductor device having a wiring line and a manufacturing method thereof.
2. Description of the Related Art
In a method employed to increase the packaging density of a semiconductor device, a semiconductor construct called a chip size package (CSP) is provided on a base plate having a planar size greater than that of the semiconductor construct. Jpn. Pat. Appln. KOKAI Publication No. 2004-71998 discloses the structure of such a semiconductor device and a manufacturing method thereof. In the semiconductor device disclosed in this prior literature, an insulating layer is provided on the base plate around the semiconductor construct. An upper insulating film is provided on the semiconductor construct and the insulating layer. An upper wiring line is provided on the upper insulating film so that this upper wiring line is connected to an external connection electrode (columnar electrode) of the semiconductor construct.
In the meantime, in the conventional semiconductor device manufacturing method described above, it is necessary to form an opening in a part of the upper insulating film corresponding to the center of the upper surface of the columnar electrode of the semiconductor construct in order to connect the upper wiring line formed on the upper insulating film to the columnar electrode of the semiconductor construct. In this case, it is known to form the opening in the upper insulating film by laser processing based on laser beam irradiation.
On the other hand, if the diameter of the laser beam is about 50 μm which is the minimum diameter at present, the diameter of the opening to be formed in the upper insulating film is about 70 μm. In this case, when the accuracy of the laser processing is taken into account, the diameter of the columnar electrode of the semiconductor construct needs to be 100 to 120 μm. Therefore, the problem is that there is a limit to the miniaturization of the semiconductor construct and it is impossible to adapt to an increase in the number of columnar electrodes.